12 oz. dried black beans 8 cups chicken or vegetable stock 2 teaspoons olive oil 1 onion, chopped 1 cup carrots, chopped 1 cup celery, chopped 2 cloves garlic, minced 2 teaspoons dried oregano 1 teaspoon dried thyme 1 bay leaf 1/2 teaspoon cayenne pepper 3 tablespoons fresh lime juice Fresh cilantro (optional)|Rinse and sort though black beans, discarding any that are shriveled or discolored. Place beans in a large stockpot. Cover beans with water and refrigerate to soak overnight. Drain beans and return to stockpot. Add stock and heat to boiling. Meanwhle, heat olive oil over medium−high heat in a large skillet. Add onion, carrot, celery and garlic and saute until tender, approximately 5 minutes. Add to stockpot along with oregano, thyme, bay leaf and cayenne pepper. Cover stockpot and reduce heat to simmer for 3 to 4 hours. Transfer soup to blender or food processor and puree to desired thickness. Just before serving add lime juice and garnish with a sprig of fresh cilantro, if desired. Add salt and pepper to taste and serve.